1) You used the best lit upper wing from your bird to compare to the wing in the shadow from my bird. How about you show us the lower wing that is in shadow from your bird in 100%? I already see noises and red-color (banding) in your 50% cropped

Look at my original unprocessed image - the wing was not well lit - it was underexposed and was bumped 0.67EV and 75/100 pushed on shadow recovery inthe brighter image you're comparing to! The far wing was essentially pitchblack. You subject actually appears to be much more evenly lit than mine, and if you had pushed exposure and shadow recovery in post with a 5D3, it would look far worse than what you've presented - so I'm not seeing your point here at all?

BTW, as I posted a crop of the full size image, you could have checked the 100% 1:1 pixel view already - it seems you still don't get the 100% thing even though you're fixated on it being a major IQ driver?

2) You used 1/4000 shutter in your photo vs 1/1000 shutter in my photo. Aka, isn't that a better technique as from a tripod at 1/4000?

I"ll guarantee that the bird in my picture was travelling MUCH faster thatn the bird in yours, so I needed that shutter speed to freeze it's motion - I needed the same with my D4 - so I didn't pick it because of the D800's 36 MP. It's not better technique - it's just proper technique for the subject!

3) Check birds' bodies that have similar lit, then the difference is pretty clear that my one has more feather details and obvious sharper.

The bird's bodies are absolutely not similary lit as I indicated above and the bird's feathers are too different to make any definitive judgment on sharpness - but you seem to gloss over the fact that you are looking at a significantly more magnified view of a much smaller object in the frame in my shot. If I had shot your pelican side by side with you - the D800 image would be much sharper for the same FOV/image size you captured with your 5D3 guaranteed.